In recent years, tufted pile fabrics utilizing primary and secondary backings made from synthetic plastic materials have been developed for use indoors and outdoors. These carpets have utilized synthetic plastic primary and secondary backings in order to provide stability to the carpet structure and to eliminate the problems encountered previously by carpets which have been made from natural fibers. Carpets made from natural fibers are subject to shrinking and rotting in abnormal weather conditions and when liquids are spilled thereon. Additionally, such carpets are subject to excessive staining and require frequent removal and cleaning.
In U.S. Pat. No. 3,110,905 issued Nov. 19, 1963 to Rhodes and U.S. Pat. No. 3,336,178 issued Aug. 15, 1976 to Levitch, and both assigned to the same assignee as the instant application, namely, Burlington Industries, Inc., there are disclosed tufted pile fabrics utilizing synthetic plastic backings and pile yarn also made from synthetic plastic or man-made fibers. While the tufted pile fabric disclosed in these two patents have been commercially successful for installations wherein the floor covering is subjected to rotting conditions, moisture conditions from rain or spillage of liquids, they have not been completely satisfactory when used in situations wherein the carpeting is to be substantially permanently installed by adhesively securing the same to a floor structure, particularly when the primary and secondary backings are bonded together with a hot melt adhesive. With the advent of the use of hot melt adhesives and the application of such technology to the disclosures in these two patents and particularly to the disclosure in Levitch, the resulting tufted pile fabric provided greatly improved adhesion between the synthetic primary and secondary backings, effectively preventing separation of the primary and the carpet face from the secondary, when the secondary is bonded to a floor structure. Additionally, the hot melt adhesive greatly improves pile bind, effectively preventing removal of carpet tufts from the carpet face by pulling or snagging. However, a carpet with a hot melt bonded primary and secondary backing also exhibits a very firm hand which can make the fabric too stiff for practical installation. More serious however is the fact that the hot melt adhesive combines with the synthetic primary and secondary backings to form a substantially impervious sheet, a factor which has effectively prevented satisfactory water based adhesive installation of such carpets on floor structures because of lack of complete drying and subsequent unbonding or puckering of the undried areas. Water based adhesives are desired for such installations because the adhesive does not dry immediately, thus permitting flexibility and adjustment during carpet installation. Thus, when such carpeting is adhesively bonded to a floor structure by a water based adhesive, it will gradually unbond and display ripples on the edges and pockets or bulges in various places throughout the carpet apparently because the use of the hot melt adhesive for providing the bonding between the primary and secondary backing and for anchoring the tufts to the primary backing, also eliminates the breathability of the carpet to an extent sufficient to prevent adequate drying or setting of the water based adhesive in a practical time following installation.